The related "Conductive Film Magnetic Components" patent application discloses magnetic components having windings comprised of a continuous conductive film which has a serpentine configuration when disposed in a plane and which is folded upon itself to form a plurality of layers providing a current path which encircles a magnetic pole of the structure. Also disclosed therein are secondary windings interleaved with the layers of the continuous film winding to provide a transformer. The conductive film secondary windings may comprise a plurality of separate conductive films connected in parallel to provide a low resistance, high current capacity secondary winding. Such structures are particularly useful for step down transformers because they provide primary and secondary windings having substantially equal power handling capacities at high frequencies.
There are a number of applications for magnetic components which severely restrict the physical dimensions of the magnetic component. One such application is the standard electronic module (SEM) whose physical dimensions are specified by U.S. Government military standards. In particular, in order that circuit cards populated with SEM modules will fit in the electrical interconnection and conductive cooling cages which are standard for such systems, SEM modules are limited to 0.3 to 0.6 inches in thickness perpendicular to the major surface of the module.
Because of increasing system clock frequencies and decreasing power supply voltages, it is considered desirable to install small power supplies in a distributed manner on SEM's in order to minimize electrical noise and maximize voltage regulation. It is apparent from the physical dimension limitations of SEM modules that such distributed power supplies must meet tight specifications on the height of the components therein while also providing high efficiency. Transformers of the type disclosed in the related patent applications meet the current carrying capacity and power density requirements for such systems since they are capable of providing power densities on the order of 400 watts per cubic inch with good efficiency. However, when power levels exceed 50 watts or transformer ratios exceed about 10:1, the height of such transformers exceed the allowable values for the SEM module.
Consequently, there is a need for transformers of this general type which exhibit a reduced height for power levels in excess of 50 watts and transformer turns ratios in excess of 10:1.